EP2218641A1 - Current retour network element for aircraft - Google Patents

Abstract

The element (1) has a set of electrically conducting strips (2) formed from a single piece and separated from each other so as to form a set of openings (4) between the strips. The strips are intersected in a perpendicular manner to form a mesh, where intersections of the strips form a mesh node. Thickness of the strips ranges between 1 mm and 5 mm, and is equal to or less than width of the strips, where the network element is supported against an upper surface or lower surface of crosspieces (8). An independent claim is also included for a portion of aircraft, comprising a current return network element.

Description

TECHNICAL AREA

The present invention generally relates to the current return for aircraft electrical appliances on an aircraft, and more particularly relates to an aircraft current return network element.

STATE OF THE PRIOR ART

The electrical power supply of the electrical appliances on board an aircraft is usually carried out by an electric power supply cable and by a current return network produced by the structure of the aircraft.

Generally, the elements of the fuselage and its primary structure (panels, frames, smooth) are made of metal material, which allows the formation of an electrical network return functional and fault currents.

However, the structural elements of the fuselage are increasingly made of composite material comprising a mixture of fibers and resin, in order to achieve a significant mass gain while preserving or improving the mechanical characteristics of said structural elements.

Composite materials with low electrical conductivity, fuselage structure elements of composite material can no longer form a current return network.

It is then known to use the primary metallic structure of the floor or floors of the aircraft to form a network, or a network element, back current.

An aircraft floor usually incorporates longitudinal members and cross members assembled by means of metal joining means.

These metal joining means therefore achieve a structural junction, but also electrical since they ensure electrical continuity between the longitudinal members and the floor cross members, thus forming a current return network element.

However, the electrical continuity is obtained only after a so-called metallization operation performed during the production cycle.

Indeed, a protective paint against corrosion usually covers metal parts, painting that is usually not conductive. On the other hand, an interposing mastic is often present at the level of the structural junctions between the metal parts in order to avoid the phenomena of wear of contact between said parts.

The metallization operation, generally performed manually, then consists of removing the interposing mastic and stripping the paint, to locally reveal the base metal of the metal part. The connecting means can then be mounted on said piece at the prepared contact surface.

This type of current return network element, however, has some disadvantages.

The electrical junction made by the connecting means is obtained by a manual metallization operation, which can cause, therefore, some harmful imperfections.

Thus, small amounts of mastic or paint between the junction means and the metal part considered sufficient to degrade the quality of the electrical contact. This can lead to a local rise in temperature and therefore premature fatigue of the parts, as well as a local alteration of the electrical conductivity.

In addition, the use of joining means makes it necessary to perform a large number of metallization operations, preferably one for each of said joining means. This operation, manual, significantly extends the production cycle of the aircraft. The monitoring and maintenance cycle of each junction is also particularly increased. This necessarily leads to high costs of implementation and maintenance.

STATEMENT OF THE INVENTION

The main purpose of the invention is to present a current feedback network element at least partially overcoming the disadvantages mentioned above relating to the embodiments of the prior art.

To do this, the subject of the invention is an aircraft current return network element comprising a plurality of intersecting electrically conductive strips and made in one piece, spaced apart from one another so as to form therebetween plurality of openings.

Thus, the current return network element according to the invention has electrical and structural junctions naturally formed by the intersections of said strips, because the network element they form is made in one piece. In other words, by the realization of said network element in one piece, said strips intersect without being superimposed on each other at intersections. It is then not necessary to provide reported means to ensure the electrical connection between said strips. The risk of loss of connection between the bands is thus eliminated.

Any degradation of the electrical properties at the junctions, here crisscrossings, is then discarded.

In addition, the invention makes it possible to substantially reduce the production cycle time since the metallization operations previously described are no longer necessary. The duration and maintenance costs of the line return network are also particularly reduced compared to the prior art described above.

Moreover, the number of bands can be high so as to form a particularly fine mesh, in order to obtain a network element with high reliability. Unlike the prior art, the number of bands, and therefore the number of intercrossings, does not increase the potential risks of degradation of electrical properties, or the duration of production and maintenance cycles.

Furthermore, the geometry of said network element is easily adaptable to that of any aircraft part that is to be equipped with such a network element. By way of example, the arrangement of the intersecting bands, and that of the openings, can be chosen according to the geometry of the aircraft elements along which it is desired to route said strips.

Each band is preferably rigid.

Preferably, said openings are arranged substantially periodically.

Preferably, said intersecting strips are substantially perpendicular to each other so as to form substantially rectangular or square openings.

Advantageously, the network element is monolithic. In other words, said strips are made of the same material, which makes the electrical conductivity substantially homogeneous within said strips. Any abnormally high temperature zones located at the interfaces between different materials are thus removed. The risks of premature fatigue of the network element are therefore reduced.

The material may be selected from those having a high conductivity in order to limit the voltage drop along the network element.

Advantageously, the network element has a generally wavy shape. By general wavy form means a general shape having or having regular and parallel corrugations. The mechanical strength is then reinforced by the presence of the corrugations.

Preferably, the thickness of said strips is between 1mm and 5mm. The thickness is preferably substantially constant along each strip, and substantially the same for all said strips.

Preferably, said strips are intersecting substantially perpendicularly.

The invention also relates to an aircraft part comprising at least one current return network element according to any one of the characteristics mentioned above.

According to one embodiment of the invention, said aircraft part comprises a floor comprising a plurality of cross members, a network element being in abutment against said crosspieces. Thus, said sleepers have a support function, or maintenance of said network element. Moreover, it can participate in the structural strengthening of said floor.

Said network element may bear against the upper or lower surface of said sleepers.

Said aircraft part may comprise floor rails, said network element being interposed between said rails and said sleepers. Said network element is then preferably supported against the upper surface of the crosspieces.

Said rails can be seat rails mounted on a passenger floor, or freight rails mounted on a so-called cargo floor.

Said aircraft part may also comprise at least one electrical power supply cable support, said cable support being mounted on said network element by holding means. Said network element is then preferably supported against the lower surface of the sleepers.

According to another embodiment of the invention, said aircraft part may comprise a fuselage portion comprising a plurality of structural frames, said network element being in support against said frames. Said network element can then participate in the structural reinforcement of said fuselage portion.

Other advantages and features of the invention will become apparent in the detailed non-limiting description below.

BRIEF DESCRIPTION OF THE DRAWINGS

• La figure 1 est une vue de dessus d'un élément de réseau de retour de courant selon le premier mode de réalisation de l'invention ;
• La figure 2 est une vue en coupe transversale d'un tronçon de fuselage représentant des possibilités de montage de l'élément de réseau de retour de courant sur un plancher passager ;
• La figure 3 est une vue en perspective du tronçon de fuselage représenté sur la figure 2, montrant plus particulièrement les traverses et les rails de plancher ;
• La figure 4A est une vue de dessous d'un élément de réseau de retour de courant selon un second mode de réalisation de l'invention représenté sur la figure 2, comprenant des moyens de maintien d'au moins un support de câbles d'alimentation électrique ;
• La figure 4B est une vue partielle et agrandie en coupe transversale suivant le plan I-I de la figure 4A, montrant un exemple de support de câbles assemblé par lesdits moyens de montage à l'élément de réseau de retour de courant ; et
• La figure 5 est une vue en perspective d'une partie d'un élément de réseau de retour de courant présentant une forme générale ondulée.

Embodiments of the invention will now be described, by way of nonlimiting examples, with reference to the accompanying drawings, in which:

• The figure 1 is a top view of a current return network element according to the first embodiment of the invention;
• The figure 2 is a cross-sectional view of a fuselage section showing mounting possibilities of the current return network element on a passenger floor;
• The figure 3 is a perspective view of the fuselage section shown on the figure 2 , particularly showing sleepers and floor rails;
• The Figure 4A is a bottom view of a current feedback network element according to a second embodiment of the invention shown in FIG. figure 2 comprising means for holding at least one power supply cable support;
• The Figure 4B is a partial view and enlarged in cross section along the plane II of the Figure 4A showing an example of cable support assembled by said mounting means to the current return network element; and
• The figure 5 is a perspective view of a portion of a current feedback network element having a generally wavy shape.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The current feedback network element 1 according to the first preferred embodiment of the invention is shown schematically on the figure 1 in top view.

Throughout the following description, by convention, X is referred to as the longitudinal direction of the aircraft, Y is the direction transversely oriented relative to the aircraft, and Z is the vertical direction. three directions jointly forming a direct orthogonal reference.

On the other hand, the terms "front" and "rear" are to be considered in relation to a direction of advancement of the aircraft obtained as a result of the thrust exerted by the engines of the aircraft, this direction coinciding substantially with the X direction.

The network element 1 according to the invention comprises a plurality of interleaved electrically conductive strips 2 made in one piece, spaced apart from each other so as to form therebetween a plurality of openings 4.

Said strip is a piece whose length is much greater than its width, for example twice as long.

The thickness of said strip may be equal to or less than its width, preferably less.

The thickness may be between 0.5 and 15 millimeters, preferably between 1 and 5 millimeters.

Each band 2 has a substantially constant thickness and width. In addition, the thickness and width are substantially identical for all said strips 2.

Said strips 2 are electrically conductive, for example aluminum or in one of its alloys. Preferably, they are made of a material whose electrical conductivity is sufficient to allow the return of the current, both being resistant to corrosion.

Said strips 2 intersect so as to form a mesh where each interlacing 3 forms a node of the mesh. They are spaced apart from each other so as to form between them a plurality of openings 4. By opening means a void space passing through said network element.

Said openings 4 are arranged in a substantially periodic manner, and said strips 2 forming a crisscrossing 3 are substantially perpendicular to each other, so as to form openings 4 substantially rectangular or square.

Said strips 2 are made in one piece, so as to jointly form a single piece. No insert is therefore necessary to ensure the structural junction between said strips. In addition, the strips intersect without being superimposed on one another at the crisscrossing.

The figure 2 shows a cross section of a fuselage 5 having a passenger floor 6.

A current return network element 1, as described above, can be mounted on the floor 6, more precisely on the primary structure of the floor 6.

As shown in figure 3 , the primary structure comprises a plurality of longitudinal members 7 extending in the longitudinal direction X of the aircraft, and a plurality of cross members 8 extending in the transverse direction Y.

Generally, each cross member 8 is made in one piece and extends in the Y direction over the entire width of the floor structure 6.

The cross members 8 and the longitudinal members 7 may be made of metal or composite material comprising a mixture of fibers and resin.

It should be noted that it is no longer necessary to perform the metallization operation described above at the junction made by the junction joining means ensuring the assembly of the cross members 8 and the longitudinal members 7.

Said network element 1 can bear against the upper surface 8A or lower 8B of said crossbars 8.

By bearing against is meant disposed in direct or indirect contact against said sleepers 8. The indirect contact can be achieved by means of an interposing mastic.

The terms "upper" and "lower" are to be considered in relation to the vertical direction Z of the aircraft.

The network element 1 can be fixed to the cross members 8 by riveting or bolting, or by lockable connectors.

Preferably, said network element 1 comprises, for each floor 8, a strip 2 disposed opposite said crossbar 8, as shown in FIG. figure 1 where each dotted line symbolizes a cross 8. Thus, said strip runs along said cross member 8 opposite which it is arranged.

Said network element 1 may have a number of strips 2 opposite said sleepers 8 less than the number thereof. For example, a strip 2 may be arranged facing a crosspiece 8 every two or three sleepers, or more. Said network element 1 then has a reduced mass, thereby participating in the general requirement of mass saving.

Moreover, figures 2 and 3 show metal rails 9 which can be mounted on the floor structure, for example rails 9 ensuring the attachment of passenger seats (not shown).

The rails 9 usually extend along the longitudinal axis X of the fuselage and are connected to each other by cross members 8 which extend perpendicular thereto.

Said network element 1 is then advantageously interposed between said rails 9 and said sleepers 8.

Preferably, said network element 1 comprises strips 2 oriented in the longitudinal direction of the rails 9.

Advantageously, a strip 2 is disposed facing each rail 9.

Thus, strips may follow said rails 9 and other strips of the same network element 1 may follow said sleepers 8.

Advantageously, said rails 9 participate in the formation of the current return network by electrically connecting the electrical devices possibly disposed at the passenger seats to said network element 1 back current.

Furthermore, the current return network may comprise a network element 1 resting on the upper surface 8A of the cross-members 8 and / or a network element 1 bearing against the lower surface 8B of the cross-members 8.

In the case of a network element 1 resting against the lower surface 8B of the cross members 8, and as shown by the figures 2 and 4A , supports 10 of power supply cables, as described in the patent application FR2905038 filed in the name of the applicant, can be mounted on said network element 1.

Said supports 10 for electrical cables may comprise a profiled metal body 11 which participates in the return of the current flowing in the cables.

Each cable support 10 can be mounted on said network element by means of holding means 12 ( Figure 4B ).

Said holding means 12 may be metallic, so as to ensure electrical continuity with said cable supports.

Said supports 10 can also provide harness support, and participate in protection against the indirect effects of lightning.

These holding means 12 may be a pair of U-shaped rails 12 welded or fixed to the lower surface of said network element 1, as shown in FIG. Figure 4B . The two rails 12 are arranged so as to cooperate with the T-shaped profiled body 11 of said cable support 10.

In the example of the Figure 4A said holding means 12 extend all along said network element 1 in a continuous manner. They can alternatively extend discontinuously.

These cable supports 10 can thus improve the structural rigidity of said network element 1.

Preferably, each network element 1, whether resting on the upper surface 8A or lower 8B of the crosspieces 8, extends in the transverse direction Y over the entire width of the floor 6.

Furthermore, said network element 1 can be mounted on frames 13 of the fuselage structure of the aircraft, by fastening means 14 arranged at its side edges, as shown by FIGS. Figures 1 and 2 . It can be fixed by riveting or bolting, or by lockable connectors.

These frames 13, to the extent that they are metallic, can participate in the formation of the current return network and thus cooperate with said network element 1 back current.

In general, said network element 1 advantageously has a modular structure, and thus allows the arrangement along the longitudinal direction X and / or the transverse direction Y of a plurality of successive network elements 1 so that extend substantially over the entire length and / or width of the floor 6.

In the case of a disposition in the longitudinal direction X, and as shown in figure 1 each network element 1 then comprises means 15 of electrical junction for ensuring electrical continuity between the neighboring network element 1. These means 15A, 15B of electrical junction may be contact areas disposed respectively on the front portion of a first network element 1 and on the rear portion of the second network element 1 consecutive.

In the same way, in the case of a disposition in the transverse direction Y (variant not shown), electrical connection means 15 may be provided at the lateral edges of each network element 1.

Of course, each network element may comprise electrical junction elements for the purpose of arranging a plurality of network elements 1 at a time in the longitudinal X and transverse Y directions.

It should be noted that although the figure 2 describes a current return network element mounted on a passenger floor 6, said network element can also be mounted on a so-called cargo floor 16 for goods.

In an embodiment not shown, said network element can be in abutment against a plurality of fuselage frames 13, on a longitudinal portion of the fuselage 5. Thus, while participating in the rigidity of this fuselage portion, said element of network 1 ensures the return of current of electrical devices that can be placed in an upper or lower part of the fuselage 1.

Said network element may also have a modular structure as described above.

Finally, the network element 1 may have a generally wavy shape.

By general wavy form means a general shape having or having regular and parallel corrugations.

As illustrated by figure 5 the network element comprises a first plurality of strips 2 extending in a first direction, which intersects with a second plurality of strips 2 extending in a second direction. The intercrossing and the one-piece production of said strips are identical to what has been described above.

The first and second directions here are substantially orthogonal and coincide substantially with the longitudinal X and transverse Y directions, respectively. Alternatively, they can define between them a non-zero angle other than 90 °.

Each strip 2 of said first plurality 17 extends substantially plane in the direction X, while each strip 2 of said second plurality 18 extends undulated substantially in the direction Y. Thus, the strips 2 of said second plurality 18 each have a succession of concave portions and convex portions.

For each waving period, said first plurality of strips 2 comprises a band 2A defining the high peak of the wave considered. and a band 2B defining the low peak of said ripple.

The network element 1 may comprise fixing openings disposed at the level of the intersections between each of the strips 2A and the strips 2 of the second plurality 18. Also, the network element 1 may be mounted, for example, on a floor aircraft through the strips 2A placed against the floor as described above. Mounting means, such as rivets, bolts or lockable connectors, are then arranged through the fastening openings.

The strips 2B are then not in support against the floor, and can in particular be used to maintain harnesses.

It should be noted that the general shape of the network element remains here substantially flat. Indeed, the set of bands 2A of the first plurality 17 is substantially contained in the same plane. Similarly, the set of bands 2B is substantially contained in the same plane, the latter being parallel to the plane of the bands 2A.

Alternatively, the general shape of the network element 1 can be substantially curved, especially when it is mounted on a plurality of fuselage frames of a fuselage portion, as described above. In this case, the set of strips 2A of the first plurality 17 is substantially contained in the same curved surface. Similarly, the set of strips 2B is substantially contained in the same area curve, the latter being parallel to the curved surface of the strips 2A.

Whatever the embodiments described above of the network element according to the invention, it can be achieved by trimming a corrugated sheet or not, for example by laser cutting, or from expanded metal.

Of course, various modifications may be made by those skilled in the art to the invention which has just been described, solely by way of non-limiting example.

Claims (11)

Current return network element (1) for aircraft, characterized in that it comprises a plurality of intersecting electrically conductive bands (2) made in one piece, spaced apart from each other so as to form between them. ci a plurality of openings (4). Network element (1) according to claim 1, characterized in that it is monolithic. Network element (1) according to claim 1 or 2, characterized in that it has a generally undulating shape. Network element (1) according to any one of claims 1 to 3, characterized in that the thickness of said strips (2) is between 1mm and 5mm. Network element (1) according to any one of claims 1 to 4, characterized in that said strips (2) are intersecting substantially perpendicularly. An aircraft part comprising at least one current return network element (1) according to any one of claims 1 to 5. Aircraft part according to claim 6, characterized in that it comprises a floor (6) comprising a plurality of sleepers (8), a network element (1) bearing against said sleepers (8). Aircraft part according to claim 7, characterized in that said network element (1) bears against the upper (8A) or lower (8B) surface of said crosspieces (8). Aircraft part according to claim 7 or 8, characterized in that it comprises floor rails (9), said network element (1) being interposed between said rails (9) and said sleepers (8). Aircraft part according to any one of claims 7 to 9, characterized in that it comprises at least one electrical power supply cable support (10), said cable support (10) being mounted on said element network (1) by holding means (12). Aircraft part according to claim 6, characterized in that it comprises a fuselage portion (5) comprising a plurality of structural frames (13), said network element (1) bearing against said frames (13) .

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